Tierra Verde, Florida -- As the search continues, we're learning more sad details about the Pinellas Park man who fell off his boat Sunday and disappeared underwater.

Michael Rhine's wife and friends looked on as search teams from the Pinellas County Sheriff's Office and Florida Fish and Wildlife Commission headed out Monday morning.

Deputies now tell us Rhine was working on his boat's engine Sunday in the waters off Fort DeSoto Park, at the southwestern tip of Pinellas County.

He fell overboard and didn't come back up. His wife was on the boat, but could not find him.

She was crying and looked stunned as deputies brought her and their family dog back to the park late Sunday afternoon.

Crews searched for the 49-year old well into the night Sunday around Bunces Pass. They'll be using boats, helicopters, and sonar to try to find him Monday.

"Today, we're gonna be out here," Pinellas Sheriff's Sgt. David DiSano said. "We're gonna exhaust all means to try to find Mr. Rhine. By the end of the day, by the end of daylight, we're going to reassess the situation and go from there."